… any reliable metric established for initiating a point (serving), just like H% measures its termination, must ultimately be determined as a function across the continuum of the quality of any opponent being played.
~ Serving Considerations – Part One (conclusion)
There are two basic components to consider from the quotation above. [1] An interest for determining a reliable serving metric measuring the initiating of a point (one as reliable as H% is for terminating it), and [2] Recognizing even if you have such a metric, it needs to be interpreted by the quality of an opponent, just like should be done for H%, but statistically rarely ever is. i.e. I assume a good coach recognizes hitting .300 against a top 10 team in D3 is better than hitting .400 against the 80th best team, even though the statistic doesn’t differentiate this distinction. To construct a reasonable serve metric starts by assessing a team’s interest as it relates to the chances to win a point.
A team mindset as it relates to the potential to win a point when serving: “The primary objective of our server is to facilitate acquiring possession of the ball. Depending on the nature of the opponent’s pass (In System or Out of System) & our ability to get control of their attack after this fact, we will be able to average somewhere between a 54% (Opponent IS Pass) and a 70% (Opponent OS Pass) chance to win the point, if we do get possession – A far improved prospect than what existed before our server initiates the attempt (Expected probability < 38%). The most effective way to arrive at this enhanced probability is for he to serve aggressively, particularly when the opponent is highly functional. i.e. A highly functional opponent infrequently gives up possession before earning a side-out. Of course, an ace coming about resulting from that aggression, with its 100% point win probability, beats 70%, 54%, or < 38%, any day. The upside by-product this aggression produces (disrupting an opponent’s functionality) must outweigh any additional risk of error (increase in service errors as a consequence of the aggression) in order to know any degree of benefit the team achieves from it. (All probabilities above from the serve demand graphic introduced in the first post of this series last week.)
What is a reliable service metric? SER – Serve Efficiency Rating
How is it computed? There are 5 classes of service outcomes considered, each with a different value. To compute SER you find the mean (average) score per served ball. Each value is determined as it relates to the probability for a team to earn a point, and to what degree the server be credited for it . Here is how it works:
Essentially a two-pronged approach: The first is a 5 point award if the serving team gets possession. That is the primary goal because it means a 60% probability, on average, to earn a point, and before that possession occurred, the server is the only team member to facilitate this outcome. The second is a 10 point bonus for forcing an out of system (OS) pass, and an added 10 point bonus should it be deemed an ace. So this second prong becomes 20 points for an ace and 10 points for an opponent’s OS pass. Note: The team needn’t get possession in order to earn any bonuses. They are independent.
This makes the 5 classes of outcomes the following:
- Class 1: An ace is worth 20 points – Certainty in earning a point!
- Class 2: A serve whose pass is ‘OS’ and for which the serving team gains possession is worth 15 points – 70% probability to earn a point, highly attributable to the served ball.
- Class 3: A serve whose pass is ‘OS’ and for which the serving team doesn’t gain possession is worth 10 points – Only a 10% chance to earn a point, but less a function of the server’s ability than the quality of the opponent’s setter and hitter on that play, the reason it warrants this value.
- Class 4: A serve whose pass is ‘IS’ and for which the serving team gains possession is worth 5 points – 54% probability to earn a point, but likely less a function of the serve than the quality of the receive on the other side of the net. Nonetheless, the serve precipitated this possession to some degree, and that shouldn’t be ignored. This was the server’s primary mission at contact and it was met.
- Class 5: [1] A serve whose pass is ‘IS’ and for which the serving team doesn’t gain possession is worth nothing, i.e. 0 points – Even if the serving team succeeds 10% of the time by blocking or forcing the receive team to hit out of bounds, the 10% point win probability is mostly determined by the front line in combination with a receive team’s lack of execution – Not attributable to the server! [2] A service error is also 0 points because there is no chance to win the point, and this directly relates to the server’s lack of execution. No need to differentiate the two ways to earn nothing because both equally fail the initiative.
A server’s mindset as related to the metric: “Do what is required to earn a possession for my team (5 pt.) – The chances for this improve if I can get an opponent Out of System (10 pt.), or better yet, if the aggression to achieve that produces an ace, instead. (20 pt.)“
How to interpret this metric? SER is commensurate to SAT scores with 5.0 meaning 500, i.e. AVE.
How do you measure this metric as a function of the opponent?
Measuring the SER for a team and their opponent is similar to measuring H% for both. The SER of the opponent informs the ability of a team’s receive to deny the opponent’s service goals, while its SER shows the degree to which it reached them. As a team plays weaker opponents, just as with a H% metric, the expectation would be for it’s metrics to become greater (positive slope) and the opponent’s metrics to become lesser (negative slope). The intersection of these graphs is a rough predictor of a team’s National Rank, just as it is for H%. There are at least two things that matter most regarding the graphs below as you scroll left or right, comparing SER# & HIT% across the National Rank spectrum. (Keep in mind these are regression lines being shown, without the actual data points to simplify the message.)
[1] The “steepness” of their slopes indicates the degree a team performs a skill independent of a changing strength of an opponent. For example, a lesser slope meaning the change in opponent’s strength (its national rank) affects a team to a lesser degree. A steeper line indicating a greater affect on its performance of a skill for smaller changes in an opponent’s resistance, as determined by its national rank.
[2] The gold line is the difference (delta) between a team’s and its opponent’s metric. So where the red and blue line intersect, the gold line will be zero, the point for which a team and its opponent’s H% or SER metric is equal. Exactly like a break-even point for when Revenue equals Cost, making Profit = $0 in economics, really. The gold line suggests the degree better or worse a team is compared to an opponent on the spectrum in the skill category, found by subtracting its opponent’s metric from its own.
A Graphic Showing All the Above & Indicating Point Scoring?
The feather graphic shows ACES in BLUE and SERVICE ERRORS in RED in chronological order of a match, left to right. All winning points are barbs above the mid-line and all losing points below it, the length of each indicating how many possessions a serving-team had in a point. Longest barbs are 0 serving team possessions, such as terminal and first ball side-outs. They become progressively shorter as a serve’s influence on a point becomes less. Half length for 1 serve-team possession, one-third length for 2 possessions, one-fourth for 3 possessions, etc. Black barbs are serves putting an opponent out of system and gray barbs are passes in system by the receiving team. The end of a set in the match is indicated by a double black mark on the mid-line.
The feather seen below was against Wentworth Tech’s receive on 1/21/23 for St. John Fisher serving to it. For those who remember, Laboo suffered a severe hand injury in the middle of this match. Notice the density of winning points by Fisher (upward barbs) on the right side of the feather, illustrating Wentworth’s decreased ability to side-out without him later on that day. Ironic this match precipitated these two team’s second consecutive first round NCAA Tournament meeting in as many years, with Fisher the #7 seed to Wentworth being a #10, certainly dependent on this injury, even though by the time April came Wentworth was at least who they had been the year before when they advanced to a National Semi- Final.
The feathering graphic can expand across a whole season or parts of seasons against varying opponents as seen above. Harder to explicitly see the details, but the density of colors and barbs across each opponent informs a reader, not so unlike a satellite image might do for gathering intel for a military mission. Certainly not implying the two are even remotely on par with each other in the grand scheme of things!
Remember, every blue barb is a 20 point serve, every black barb is a 10 point serve, and every barb a distance half or less than the longest ones to the mid-line, regardless of its color, is a 5 pointer, the serving team having earned a possession. The downward barbs that are full length, red or gray, are service errors or first ball side outs with the opponent in system. Each is a 0 point outcome, having failed to achieve the goal when serving the ball.
The slide shown below is from a ’22 VNL Final match between USA & France demonstrating how to interpret a whole team serving performance looking at its feather, then placing individual player’s serving performance into focus against the same opponent. It shows how to interpret a vast amount of pertinent information from the graphic.
Notice, at the highest level of this game, there were only 2 times France’s receive relinquished no possession points to USA’s serve while in-system over this 5-set match. (longest gray barbs above the mid-line) These are hitting errors by France while in system i.e. Either hit o-b or blocked. Scan back above to see the density of longest gray barbs above the mid-line in the 5-set match with Fisher serving to Wentworth – There were 16. Likely not a fair representation for top level D3 ball with Laboo’s injury mid match. So I went and looked at last year’s championship match with Stevens and North Central, a 4-set affair. NC’s receive relinquished no possession points to Stevens’ serve while in system 12 times and Stevens’ receive just a mere 5 times when NC served without gaining possession. This shows how unbelievably functional Stevens was last year (presumably still are this year, too)! It just goes to illustrate the high degree offenses show as skill and athleticism reach new heights, making command over ball control border on perfection, and any attempt by those of the same realm to stop it, near futile.
I chose these two players in this one match to demonstrate how the SER metric can be used in conjunction with a feather. DeFalco’s SER# for the match was 6.7 (Like a 670 SAT if you are thinking about what it means.) Russell’s for the match was 4.7, (Think 470 on an SAT) Neither earned the one ace, nor did they generate any of those two non-possession points for USA’s serve, either. However, the number of OS passes France had when DeFalco served were enough, together with the USA possessions earned even when they weren’t, to result in an admirable serving day for Falco. A little less than desired for Russell. For more real-time context, I placed a “Running SER” line graph for this whole match, tracking it relative to the gold line 5 standard, the minimal goal a player seeks when serving the ball. This kind of makes the SER a “Strive for 5″ metric. Remember, 5 points is the award for a serving-team gaining possession, and possession is what any serving-team seeks to obtain from a served ball.
Here is the really cool thing, if you like any of the above. It only requires 4 key strokes after a server contacts the ball, 5 if his jersey number is “double digits”, LOL. Better yet, you only need to push 4 buttons on a touch screen, one from any of six player’s jerseys or names, then 1 each from 3 conditions observed having watched it unfold: AEIO – 0123 – WL
- Player # – What is the number on his jersey?
- Condition #1: AEIOU – The vowels LOL… A = Ace; E = Error; I = In-system Pass; O = Out-of-system Pass, and U means all “YOU” have to do is record one of these 4.
- Conditions #2: # Possessions – How many times did the serving team possess the ball? Feel free to record 3 if it gets there.
- Condition #3: W or L – Did the serving team score a point or not?
By the way, the feather graphic is really just a bar graph on MS Excel with really skinny bars. LOL
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